1. Technical Field
The present invention relates to a flow path unit including a liquid flow path through which liquid flows, a liquid ejecting head including the flow path unit, a liquid ejecting apparatus, and a flow path unit manufacturing method.
2. Related Art
Known has been an existing liquid ejecting head including a liquid flow path through which liquid flows. The liquid ejecting head has a configuration in which an opening for filling the liquid and an opening for ejecting the liquid are connected through the liquid flow path. The liquid ejecting head is formed by superimposing a plurality of substrates. The liquid flow path is also formed by combining grooves and holes formed in the respective substrates (for example, see JP-A-2007-309328).
Disclosed is a configuration in which the liquid flow path is coated with a coating film in order to protect a wall surface of the liquid flow path from the liquid (for example, see, JP-UM-A-5-60844 and JP-A-10-250078).
When the substrates constituting the liquid ejecting head are fixed to each other, the coating film formed on the substrate inhibits the fixing of the substrates in some cases. In this case, it is necessary to remove the coating film by, for example, washing a portion of the substrate on which another substrate is superimposed after the coating film is formed on the substrate. Alternatively, it can be also considered that the coating film is formed on the liquid flow path after the substrates are fixed to each other. In this case, it is, however, difficult to form the coating film appropriately in some cases when the liquid flow path is sealed by the substrate or when the configuration of the liquid flow path is complicated.